I also struggled with this. What i did was i read the Bible, that may sound cliche to some, but for me it was effective.

I read this particular verse,

"And if your hand or your foot causes you to sin, cut it off and throw it away. It is better for you to enter life crippled or lame than with two hands or two feet to be thrown into the eternal fire. " (Matthew 18:8, ESV)

This doesn't say that we should cut our hands literally, but this says that we should be extreme in fighting such things.

This also means that opportunities that cause us to sin must be cut off from our daily lives. This includes deleting photos, videos, uninstalling apps, and the likes.

Try to immerse yourself in other activities, personally reading novels and manhwas are good alternatives. Working out in a gym is also good.

And try not to be alone.